1. Field of the Invention
The present invention relates to a stubby antenna and more particularly to a stubby antenna including a novel radiating element for wireless communications devices such as cellular telephones or the like.
2. Description of the Related Art
It has been found to be desirable to provide an antenna for wireless communications devices such as cellular telephones wherein the antenna has the ability to resonate at two frequencies. In the past, to enable an antenna to resonate at two frequencies, it was necessary to have two radiating elements. One practice is to make two separate elements, specifically a coil and a straight wire which are then crimped to a common connector. Another practice has been to make a coil which has two or more different pitches. The single coil with a dual/variable pitch has the advantage of fewer parts and one less assembly operation. However, the RF performance of the single coil approach is not as good as using two elements. When a stubby antenna is being designed, it is desirable to have the stubby antenna as short as possible while maintaining the RF performance.
A dual band stubby antenna is described for use with a wireless communications device such as a cellular telephone or the like having an antenna mounting opening formed therein. A RF conductive connector stud is received within the antenna mounting opening of the communications device. The stud is press-fitted into one end of an elongated body member which extends from one end thereof. The body member has a central opening formed therein which is adapted to receive a coilform having a coil radiating element received therein. The coil radiating element is preferably mounted on a coilform having an axial bore formed therein. The radiating element comprises a first plurality of coils and a second plurality of coils with the first plurality of coils having a different pitch than the second plurality of coils. The radiating element also includes a center wire which extends from one end of the radiating element through the coils. One end of the radiating element is in contact with the inner end of the connector stud. A sheath embraces the body member with the sheath, radiating element, connector stud and body being arranged so that the radiating element is held in compression, ensuring a good electrical contact being made between the connector stud and the radiating element. The antenna of this invention provides a multiple response frequency radiating element for a mobile wireless communications device with the center wire of the radiating element enabling the actual length of the radiating element to be reduced while maintaining an acceptable electrical performance.
It is a principal object of the invention to provide a stubby antenna including a multiple frequency response radiating element.
A further object of the invention is to provide a radiating element for a stubby antenna wherein a center wire is utilized to enable the actual length of the radiating element to be reduced while maintaining an acceptable electrical performance.
Still another object of the invention is to provide an antenna of the type described above wherein the connection between the radiating element and the antenna connector is maintained by compressing the radiating element.
Still another object of the invention is to provide an antenna of the type described above wherein the number of parts normally required has been reduced.
Still another object of the invention is to provide an antenna wherein the antenna is simple to assemble since the parts snap together with no additional operations being required.
These and other objects will be apparent to those skilled in the art.